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Sorry for bad pic., the first sunny days in month`s...

When tracing the reason for "Check engine" message, I find the result as you can see in the pic. when reading live data. I assume the readings should be more or less the same on bank 1 and 2. In which directions does this info send me order to sort this out? Is it as simple as a sensor? When deleting the error codes, i can drive like 400 to 500 km, then the message comes back. However, the error code that leads to "Check engine" is P0421, which is bank 1
The "misfire counter" increases when the engine is running, but misfires on each cyl shows 0 misfires. So is there misfires?
It`s a Panamera 4S, but when searching threads its more cases of cat problems in the Cayenne section, so that`s why I Choose this section.

 

As far as misfires, you can scan and check which cylinder is being affected. Your scanner should monitor each cylinder with its own counter.
It should be one of the cylinders on the passenger side (Bank 1) but check all eight.

Misfires are most commonly addressed by replacing spark plugs and very likely coils. Make sure to get the good ones from reputable source.

As far as the P0421, that is for your passenger side primary catalyst performing below threshold.
If you address the misfires swiftly you might be able to save the catalyst with some cleaner like Techron or CataClean etc. Otherwise, you will need to replace it.
If your car burns lots of oil, this could be the related to your situation, but you would most likely get a cell for driver side as well (P0431). So hopefully just a tune up.

 

Thank`s for your reply, and tips. The strange thing is that the scanner show 0 misfires on all 8 cyl. The only misfire counter is the one that count the total. So, this means that there is misfires..?
Have been doing some scanning in live test mode this evening, and what I find is all figures are more or less the same on both banks. Specially the up- and downstream temp at cat. The are equal on all revs under all conditions (idling, slow, fast, with load, acceleration etc.)
I do get the same reading on the K040 - 0. Oxygen sensor upstream is 1,9 volt on both bank`s, and 0,7 volt on downstream. Same with the lambda upstream. Equal on both bank`s. Could this be as simple as sparks, and perhaps coils? Anyway, cheap an easy to fix.

 

Could be a failing downstream O2 sensor on the passenger side.

 

I see a lot of misunderstanding of what it means when your "check engine light" (MIL: Malfunction indicator Lamp) is on and what the "codes" (DTC: Diagnostic Trouble Codes) mean. Let's discuss this a bit in general terms that apply to most vehicles and situations. As with everything, there are always Nox Vidmate VLC exceptions.

 

The MIL tells that "something" is wrong, and the DTC point in a direction of possible causes for the MIL to illuminated, as I see it.
I usually delet all codes, and then make a new reading after starting/driving or when the MIL flashes again. Just in order to make sure that it is the right codes/errors I focus on.